Schottky Barrier Diode Guard Ring for Leakage Current Stability
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Solution Overview
Problem
The existing methods for embedding Schottky barrier diodes in semiconductor integrated circuits face challenges in reducing characteristic variations, particularly due to variations in the sputter etching process, which affect the reverse leakage current and device performance.
Innovation Solution
The solution involves arranging contact electrodes of the Schottky barrier diode over a guard ring in contact with the peripheral isolation region, rather than directly over the Schottky junction region, to minimize the impact of process parameters on device characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If contact electrodes are arranged directly over the Schottky junction region, then sufficient current can be ensured, but reverse leakage current varies significantly due to sputter etching process variations
Solution Approach 1:
The patent introduces a guard ring structure as an intermediary element between the Schottky junction region and the contact electrodes. The guard ring is formed by doping a peripheral region with a conductivity type opposite to the semiconductor substrate, creating an intermediate zone that isolates the contact electrodes from direct exposure to the Schottky junction. This intermediary structure prevents process variations in sputter etching from directly affecting the reverse leakage current characteristics.
Solution Approach 2:
The patent segments the electrode structure by separating the contact electrodes from the Schottky junction region through the guard ring. Instead of having electrodes directly contact the junction region, the structure is divided into distinct functional zones: the Schottky junction region, the guard ring region with opposite doping type, and the contact electrode region. This segmentation isolates the sensitive Schottky junction from process variations while maintaining electrical functionality.
2Reliability
If a large number of contact electrodes are densely arranged to ensure sufficient current, then device area increases, but process variations have greater impact on characteristics
Solution Approach 1:
The guard ring acts as an intermediary that allows contact electrodes to be positioned closer to the Schottky junction while maintaining electrical isolation. This enables sufficient current capability with fewer electrodes, reducing the device area occupied by the electrode array while still achieving the required current throughput.
Solution Approach 2:
The patent changes the electrical parameters of the peripheral region by doping it with a conductivity type opposite to the semiconductor substrate, creating the guard ring. This parameter change (doping type) fundamentally alters the electrical characteristics of the region, enabling it to function as an isolating barrier that reduces the number of contact electrodes needed while maintaining current capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively reduces the influence of process variations on the reverse leakage current and device characteristics, leading to more stable and reliable performance of the Schottky barrier diode in semiconductor integrated circuits.
Implementation Method 1
perform a sputter etching process with respect to the surface of a silicide (e.g., cobalt silicide) layer
Data Source
AI summary
To reduce size of a finished product by reducing the number of externally embedded parts, embedding of a Schottky barrier diode relatively large in the amount of current in a semiconductor integrated circuit device has been pursued. It is general practice to densely arrange a number of contact electrodes in a matrix over a Schottky junction region. A sputter etching process to the surface of a silicide layer at the bottom of each contact hole is performed before a barrier metal layer is deposited. However, in a structure in which electrodes are thus arranged over a Schottky junction region, a reverse leakage current in a Schottky barrier diode is varied by variations in the amount of sputter etching. The present invention is a semiconductor integrated circuit device having a Schottky barrier diode in which contact electrodes are arranged over a guard ring in contact with a peripheral isolation region.